The touch panel is one of a variety of devices for providing interfaces between users and information and communications devices which use a variety of displays. Specifically, the touch panel is an input unit through which the user can interface with the information and communications device by directly touching its screen with their finger or pen.
The touch panel allows users to interactively and intuitively operate a computer or the like simply by touching buttons displayed on its display with their finger so that men, women, and children can easily use it as an input device. Thus, touch panels are applied to a wide variety of fields such as PDAs, LCDs, CRTs, equipment for banks or public offices, various medical equipment, travel guides, and guidance equipment for main facilities, and transportation guides.
Operating or implementing types of the touch panel include a resistive (or capacitive) film type, an SAW (surface acoustic wave) type, and an infrared matrix type. The resistive film type touch panel has a panel structure with a chemical agent coated between a glass and a thin film and thin metal plates attached to X and Y-axis sides of the panel. When power is supplied to a panel of this type, a specific resistance is created through the panel. Then, if a finger or other object touches a position on the panel, the chemical agent reacts to instantly change resistance at the position. The resistance change is detected at the metal plates on the sides of the panel and coordinates of the touched position are determined from the detected resistance change.
The infrared matrix type panel has horizontal and vertical infrared emission and detection arrays that are arranged on four sides of the panel to produce infrared rays in the shape of very closely crossed grids on the panel. When an object touches a position on this panel, the object blocks an infrared ray that propagates through that position and the blocking is detected to acquire position information of the touching object.
The infrared type touch panel is generally constructed as follows. A controller is provided on a portion of a PCB plate and a display unit is provided on a portion of the panel. A non-reflective acrylic plate is provided on a front surface of the display unit. A plurality of pairs of horizontal infrared emitting and receiving elements is provided on upper and lower edges of the panel and a plurality of pairs of vertical infrared emitting and receiving elements is provided on left and right edges of the panel to create an infrared matrix. A screen is provided on a rear surface of the display unit. When a user touches a portion of the infrared matrix created by the infrared emitting and receiving elements with their finger, an infrared ray at the portion is blocked to detect the position of the portion. The infrared matrix is controlled by the controller formed on a portion of the PCB plate.